1. Field of the Invention
The present invention relates to a recording apparatus that discharges a liquid from a recording head to record an image onto a recording medium.
2. Description of the Related Art
A recording apparatus such as a printer, a copier, or a facsimile machine includes a recording head and a conveying unit. The recording head discharges ink, which is a liquid, onto a flat recording medium such as paper or a plastic sheet. The conveying unit conveys the recording medium to a position facing the recording head.
The recording head is carried by a carriage that can reciprocate in a direction (hereafter referred to as a main scanning direction) orthogonal to a recording medium conveyance direction. The recording apparatus discharges ink onto the recording medium with the reciprocating movement of the carriage. This allows a recorded image to be formed on the recording medium.
To obtain a recorded image of favorable image quality, it is necessary to accurately reciprocate the carriage in a state where a gap (hereafter referred to as a paper gap) between the recording head and the recording medium is maintained within an appropriate range. Accordingly, the carriage is supported slidably on a guide shaft extending along the main scanning direction (for example, see Japanese Patent Application Laid-Open No. 2000-198244, Japanese Patent Application Laid-Open No. H07-276736, and Japanese Patent Application Laid-Open No. 2004-042346).
Furthermore, a recording apparatus having a function of adjusting the paper gap is disclosed in Japanese Patent Application Laid-Open No. H07-276736 and Japanese Patent Application Laid-Open No. 2004-042346.
However, the recording apparatus disclosed in the above-mentioned patent documents has the following problem. A surface (hereafter referred to as a contact surface) of the carriage in contact with a guide unit slides during a recording operation of the recording apparatus. This causes the contact surface to gradually abrade each time the recording apparatus is used. The abrasion of the contact surface changes the paper gap, as a result of which the image quality of the recorded image decreases.
Though the recording apparatus disclosed in Japanese Patent Application Laid-Open No. H07-276736 and Japanese Patent Application Laid-Open No. 2004-042346 includes the function of adjusting the paper gap, this function does not cope with the change of the paper gap caused by the abrasion of the contact surface.
Therefore, in the case of continuing to use the recording apparatus, the change of the paper gap caused by the abrasion resulting from the reciprocating movement of the carriage becomes not negligible. This leads to a decrease in durability of the recording apparatus.